Inside the Plasma Control System (PCS), Operating System (OS) noises usually bring latency measured in microseconds, which make the PCS hard to satisfy the increasing complexity of advanced plasma control requirements. Analysis shows that schedule and interrupts are the main cause of latency. In order to avoid scheduling, real-time priorities are applied in control processes, and related system adjustments are done. In order to decrease the frequency of interrupts, device interrupts are migrated and a revised kernel with fewer ticks is adopted. These work turn out to be efficient to reduce latency, and sufficient time is reserved for data acquisition, computation, and transmission.